Sinclair ZX80 / ZX81 / Z88 Forums

The original power supply is sadly enough not working at all... So I bought a cheap universal power adapter that could run 9v 1A and it seems to work. So this addon is indeed a sound-mod that beeps every time you press a button and it is quite high pitched, so I'm kinda on the fence if I am going to...

I haven't powered it up yet as I have some small issues. Sadly I don't have a multimeter yet so I am unable to do a reading of the voltages on the power supply. Second issue I have is that none of the outlets I have will fit the existing plug on the power supply (it doesn't have ground nodes and all...

Before I power up the system, is there anything that I need to doublecheck, like caps that need replacing and the likes? I wouldn't want to break my lovely ZX81!

I have the original power brick, which I will connect through a Surge protector that is properly grounded.

Can you please tell me where the red and blue wires go on the ZX81 board, or post up photo(s) showing this. A photo of the underside of the sound board would be useful as well. Here a picture of the whole underside of the board with the connection points for the red and blue wires circled: IMG_2021...

So, I recently received a ZX81 from a friend's father who used to be a electrician, he has had this Issue3(?) ZX81 from its inception. When I opened it up, to check for any issues before turning it on, I found a strange board with a piezo speaker attached to it. So I suspect it is some sort of sound...